Cracks can occur in concrete as well as masonry works and can cause distress of the structure. Cracks can happen because of high ambient temperature, low humidity, improper curing, poor quality and improper combination of materials and above all poor workmanship.
Vertical cracks in brickwork can happen because of foundation movement, thermal movement, overloading, drying shrinkage, differential expansion between various members, shrinkage, etc. These cracks usually occur at the corners, below the window openings, around staircase openings, at the junctions between old structures and new extensions, at the junctions of reinforced cement concrete (RCC) columns or lintels and masonry works, etc.
Horizontal cracks usually occur below the slabs, at the lintel level or at the sill level, on the mortar joints, at the corners, etc. The main reasons for horizontal cracks are the horizontal movement due to shrinkage, lifting of the slabs, thermal gradient, drying shrinkage, differential expansion, chemical attack, ageing, etc.
Diagonal cracks can happen at the corners, especially along the cross walls even up to the foundations, over the RCC lintels, etc. Drying shrinkage, differential strain, moisture movement in the soil, etc. are some of the reasons that cause diagonal cracks.